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DTC C1912: Tire air pressure low tire1
DTC C1922: Tire air pressure low tire2
DTC C1932: Tire air pressure low tire3
DTC C1942: Tire air pressure low tire4
 
 
cautionIf there is any problem in the CAN bus lines, an incorrect DTC may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table .).
 
 
DTC SET CONDITION
When the tire pressure included in the signal from the TPMS transmitter is less than the specified value, ETACS-ECU <Vehicles without Keyless Operation System> or KOS-ECU <Vehicles with Keyless Operation System> stores this code.
 
 
TROUBLESHOOTING HINTS
The most likely causes for this DTC to be stored is:
  • Drop of tire pressure
  • Flat tire
  • TPMS transmitter malfunction
  • Malfunction of ETACS-ECU <Vehicles without Keyless Operation System>
  • Malfunction of KOS-ECU <Vehicles with Keyless Operation System>
  • CAN-bus line malfunction
 
 
DIAGNOSIS
STEP 1. Using scan tool MB991958, diagnose the CAN bus lines.
Use scan tool to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table .). On completion, go to Step 2.
 
STEP 2. DTC recheck after resetting CAN bus lines
Recheck if DTC C1912, C1922, C1932 or C1942 is stored.
(1) Turn the ignition switch (engine starting switch) from the "LOCK" (OFF) to "ON" position.
(2) Check if the DTC is stored.
(3) Turn the ignition switch (engine starting switch) to the "LOCK" (OFF) position.
Is DTC C1912, C1922, C1932 or C1942 stored?
Go to Step 3.
The procedure is complete.
 
STEP 3. Tire check
Check that there is no abnormality for the items below.
  • Flat tire
  • Cracked tire
  • Air leak from valve
Is the check result normal?
Go to Step 4.
Replace or repair it. Then go to Step 4.
 
STEP 4. Check whether the DTC is stored again.
Recheck if the DTC is stored.
(1) Turn the ignition switch (engine starting switch) to the "LOCK" (OFF) to "ON" position, and adjust the pressure to the recommended tire pressure.
(2) Check if the DTC is stored.
Is DTC C1912, C1922, C1932 or C1942 stored?
Go to Step 5.
The procedure is complete.
 
STEP 5. Check whether the DTC is stored again.
Recheck if the DTC is stored.
(1) Drive the vehicle for 5 minutes.
noteEven within 5 minutes, if the TPMS warning light goes out, finish the driving and perform the operation (2).
(2) Check if the DTC is stored.
Is DTC C1912, C1922, C1932 or C1942 stored?
Go to Step 6.
The procedure is complete.
 
STEP 6. Tire pressure check by scan tool
(1) Perform the transmitter check using the scan tool (Refer to .), and check the tire pressure values of all the wheels.
(2) Check the tire pressure of all the wheels using the tire pressure gauge.
(3) Compare the measured value (1) with (2).
OK: 20 kPa (2.9 psi) or less
noteThe TPMS transmitter which cannot be checked may be faulty or the ID code may not be registered, thus do not replace it, but register the ID code. If the transmitter is faulty, it is replace in the ID code registration process.
Is the check result normal?
Replace the ETACS-ECU <Vehicles without Keyless Operation System> or KOS-ECU <Vehicles with Keyless Operation System> (Refer to .), and register the ID codes (Refer to .). Then go to Step 8 .
Replace the TPMS transmitter (Refer to <Vehicles with steel type wheels> or <Vehicles with aluminum type wheels>.), and register the ID codes (Refer to .). Then go to Step 7.
 
STEP 7. Check whether the DTC is stored again.
Recheck if the DTC is stored.
(1) Turn the ignition switch (engine starting switch) from the "LOCK" (OFF) to "ON" position.
(2) Check if the DTC is stored.
(3) Turn the ignition switch (engine starting switch) to the "LOCK" (OFF) position.
Is DTC C1912, C1922, C1932 or C1942 stored?
Replace the ETACS-ECU <Vehicles without Keyless Operation System> (Refer to .) or KOS-ECU <Vehicles with Keyless Operation System> (Refer to GROUP 42B, KOS-ECU .) and register the ID codes (Refer to .). Then go to Step 8.
The procedure is complete.
 
STEP 8. Check whether the DTC is stored again.
Recheck if the DTC is stored.
(1) Turn the ignition switch (engine starting switch) from the "LOCK" (OFF) to "ON" position.
(2) Check if the DTC is stored.
(3) Turn the ignition switch (engine starting switch) to the "LOCK" (OFF) position.
Is DTC C1912, C1922, C1932 or C1942 stored?
Start over at Step 1.
The procedure is complete.